<html><!-- Created using the cpp_pretty_printer from the dlib C++ library.  See http://dlib.net for updates. --><head><title>dlib C++ Library - function_objects_abstract.h</title></head><body bgcolor='white'><pre>
<font color='#009900'>// Copyright (C) 2010  Davis E. King (davis@dlib.net)
</font><font color='#009900'>// License: Boost Software License   See LICENSE.txt for the full license.
</font><font color='#0000FF'>#undef</font> DLIB_MR_FUNCTION_ObJECTS_ABSTRACT_Hh_
<font color='#0000FF'>#ifdef</font> DLIB_MR_FUNCTION_ObJECTS_ABSTRACT_Hh_

<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='../matrix.h.html'>../matrix.h</a>"
<font color='#0000FF'>#include</font> <font color='#5555FF'>&lt;</font>cmath<font color='#5555FF'>&gt;</font>
<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='../svm/sparse_vector_abstract.h.html'>../svm/sparse_vector_abstract.h</a>"

<font color='#0000FF'>namespace</font> dlib
<b>{</b>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>struct</font> <b><a name='squared_euclidean_distance'></a>squared_euclidean_distance</b>
    <b>{</b>
        <font color='#009900'>/*!
            WHAT THIS OBJECT REPRESENTS
                This is a simple function object that computes squared euclidean distance
                between two dlib::matrix objects. 

            THREAD SAFETY
                This object has no mutable members.  Therefore, it is safe to call
                operator() on a single instance of this object simultaneously from multiple
                threads.
        !*/</font>

        <b><a name='squared_euclidean_distance'></a>squared_euclidean_distance</b> <font face='Lucida Console'>(</font>
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - #lower == 0
                - #upper == std::numeric_limits&lt;double&gt;::infinity()
        !*/</font>

        <b><a name='squared_euclidean_distance'></a>squared_euclidean_distance</b> <font face='Lucida Console'>(</font>
            <font color='#0000FF'>const</font> <font color='#0000FF'><u>double</u></font> l,
            <font color='#0000FF'>const</font> <font color='#0000FF'><u>double</u></font> u
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - #lower == l
                - #upper == u  
        !*/</font>

        <font color='#0000FF'>const</font> <font color='#0000FF'><u>double</u></font> lower;
        <font color='#0000FF'>const</font> <font color='#0000FF'><u>double</u></font> upper;

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font><font color='#0000FF'>typename</font> sample_type<font color='#5555FF'>&gt;</font>
        <font color='#0000FF'><u>double</u></font> <b><a name='operator'></a>operator</b><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>
            <font color='#0000FF'>const</font> sample_type<font color='#5555FF'>&amp;</font> a,
            <font color='#0000FF'>const</font> sample_type<font color='#5555FF'>&amp;</font> b
        <font face='Lucida Console'>)</font> <font color='#0000FF'>const</font>;
        <font color='#009900'>/*!
            requires
                - sample_type should be a kind of dlib::matrix 
            ensures
                - let LEN = length_squared(a-b)
                - if (lower &lt;= LEN &lt;= upper) then
                    - returns LEN
                - else
                    - returns std::numeric_limits&lt;double&gt;::infinity()
        !*/</font>
    <b>}</b>;

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>struct</font> <b><a name='cosine_distance'></a>cosine_distance</b> 
    <b>{</b>
        <font color='#009900'>/*!
            WHAT THIS OBJECT REPRESENTS
                This is a simple function object that computes the cosine of the angle
                between two vectors and returns 1 - this quantity.   Moreover, this object
                works for both sparse and dense vectors.

            THREAD SAFETY
                This object has no mutable members.  Therefore, it is safe to call
                operator() on a single instance of this object simultaneously from multiple
                threads.
        !*/</font>

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font><font color='#0000FF'>typename</font> sample_type<font color='#5555FF'>&gt;</font>
        <font color='#0000FF'><u>double</u></font> <b><a name='operator'></a>operator</b><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>
            <font color='#0000FF'>const</font> sample_type<font color='#5555FF'>&amp;</font> a,
            <font color='#0000FF'>const</font> sample_type<font color='#5555FF'>&amp;</font> b
        <font face='Lucida Console'>)</font> <font color='#0000FF'>const</font>;
        <font color='#009900'>/*!
            requires
                - sample_type is a dense vector (e.g. a dlib::matrix) or a sparse
                  vector as defined at the top of dlib/svm/sparse_vector_abstract.h
            ensures
                - let theta = the angle between a and b.  
                - returns 1 - cos(theta)
                  (e.g. this function returns 0 when a and b have an angle of 0 between
                  each other, 1 if they have a 90 degree angle, and a maximum of 2 if the
                  vectors have a 180 degree angle between each other).
                - zero length vectors are considered to have angles of 0 between all other
                  vectors.
        !*/</font>
    <b>}</b>;

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>struct</font> <b><a name='negative_dot_product_distance'></a>negative_dot_product_distance</b> 
    <b>{</b>
        <font color='#009900'>/*!
            WHAT THIS OBJECT REPRESENTS
                This is a simple function object that computes the dot product between two
                vectors and returns the negation of this value.  Moreover, this object
                works for both sparse and dense vectors.

            THREAD SAFETY
                This object has no mutable members.  Therefore, it is safe to call
                operator() on a single instance of this object simultaneously from multiple
                threads.
        !*/</font>

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font><font color='#0000FF'>typename</font> sample_type<font color='#5555FF'>&gt;</font>
        <font color='#0000FF'><u>double</u></font> <b><a name='operator'></a>operator</b><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>
            <font color='#0000FF'>const</font> sample_type<font color='#5555FF'>&amp;</font> a,
            <font color='#0000FF'>const</font> sample_type<font color='#5555FF'>&amp;</font> b
        <font face='Lucida Console'>)</font> <font color='#0000FF'>const</font>;
        <font color='#009900'>/*!
            requires
                - sample_type is a dense vector (e.g. a dlib::matrix) or a sparse
                  vector as defined at the top of dlib/svm/sparse_vector_abstract.h
            ensures
                - returns -dot(a,b)
        !*/</font>
    <b>}</b>;

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>struct</font> <b><a name='use_weights_of_one'></a>use_weights_of_one</b> 
    <b>{</b>
        <font color='#009900'>/*!
            WHAT THIS OBJECT REPRESENTS
                This is a simple function object that takes a single argument
                and always returns 1 

            THREAD SAFETY
                This object has no mutable members.  Therefore, it is safe to call
                operator() on a single instance of this object simultaneously from multiple
                threads.
        !*/</font>

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font><font color='#0000FF'>typename</font> edge_type<font color='#5555FF'>&gt;</font>
        <font color='#0000FF'><u>double</u></font> <b><a name='operator'></a>operator</b><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>
            <font color='#0000FF'>const</font> edge_type<font color='#5555FF'>&amp;</font>
        <font face='Lucida Console'>)</font> <font color='#0000FF'>const</font>;
        <font color='#009900'>/*!
            ensures
                - returns 1
        !*/</font>
    <b>}</b>;

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>struct</font> <b><a name='use_gaussian_weights'></a>use_gaussian_weights</b> 
    <b>{</b>
        <font color='#009900'>/*!
            WHAT THIS OBJECT REPRESENTS
                This is a simple function object that takes a single argument
                which should be an object similar to dlib::sample_pair.  

            THREAD SAFETY
                This object has no mutable members.  Therefore, it is safe to call
                operator() on a single instance of this object simultaneously from multiple
                threads.
        !*/</font>

        <b><a name='use_gaussian_weights'></a>use_gaussian_weights</b> <font face='Lucida Console'>(</font>
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - #gamma == 0.1
        !*/</font>

        <b><a name='use_gaussian_weights'></a>use_gaussian_weights</b> <font face='Lucida Console'>(</font>
            <font color='#0000FF'><u>double</u></font> g
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - #gamma == g
        !*/</font>

        <font color='#0000FF'><u>double</u></font> gamma;

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font><font color='#0000FF'>typename</font> edge_type<font color='#5555FF'>&gt;</font>
        <font color='#0000FF'><u>double</u></font> <b><a name='operator'></a>operator</b><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>
            <font color='#0000FF'>const</font> edge_type<font color='#5555FF'>&amp;</font> e
        <font face='Lucida Console'>)</font> <font color='#0000FF'>const</font>;
        <font color='#009900'>/*!
            requires
                - e.distance() must be a valid expression that returns a number
                  (e.g. edge_type might be dlib::sample_pair)
            ensures
                - returns std::exp(-gamma*e.distance());
        !*/</font>
    <b>}</b>;

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
<b>}</b>

<font color='#0000FF'>#endif</font> <font color='#009900'>// DLIB_MR_FUNCTION_ObJECTS_ABSTRACT_Hh_
</font>



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